This invention relates to dental equipment, and more particularly to a reusable collar for a dental impression tray.
The use of dental castings for making teeth is well known in the art. Dentists and dental laboratories have numerous devices to utilize in the making of single teeth or bridges for replacement and reconstruction of damaged portions of the patient's mouth. The usual procedure involved requires the formation of a dental impression, or a negative, directly from the patient's mouth and using that negative to make a positive casting of the desired teeth or bridge.
Dental impression trays are generally utilized for this purpose. The trays are designed to fit sections of the mouth and accordingly numerous trays are available for different sections of the mouth. A casting material is placed in the tray and the patient bites down into the casting material to make the impression. The impression tray is then removed and strick wax is rolled out from sheets and placed about the dental impression tray to build up a protective wall about the tray to retain the material poured in to make the positive impression. Numerous types of holding devices are also inserted through the walls of the strick wax to hold the dowel pins which extend downwardly into the cavity in the negative impression and which will provide the support posts for the teeth. Such items as bobby pins are frequently utilized for holding the dowel pins.
Although this procedure has been widely accepted and utilized throughout the dental profession, much of it is quite primative, cumbersome and awkward. For example, the use of the red strick wax is exceedingly bothersome and time consuming. The wax must be cut from the sheets, fitted about the tray and molded to shape the particular dental tray. This is a most awkward part of the process.
Additionally, there is no secure method of holding the dowel pins in proper position. The use of bobby pins, or other such implements which are regularly used, is a most imprecise positioning technique and often prevents the proper positioning of the dowel pins in the cavity of the (preparation) negative impression. This is especially a problem where a large bridge section must be formed and more than one pin must be utilized for the section. When trying to pull up on the dies pins to remove the (bridge wax up) positively formed piece, the bridge section may be damaged or may even crack if the pins are not both positioned properly in the same section.
Although the use of the strick wax, the bobby pins, and other such primative devices present difficulties in use, nevertheless, they still continue to be used by the dental profession as well as by dental laboratories, mainly for lack of any improved and more precise devices for facilitating the formation of dental castings.